2007 Annual Report 1a.Objectives (from AD-416) 1.) Determine crop and tillage management impacts on carbon (C) and nitrogen (N) cycling and related soil biophysical properties. 1.a.) Determine tillage and cropping system effects on soil organic and inorganic N and C dynamics, and greenhouse gas emission. 1.b.) Evaluate performance of modified CQESTR to estimate tillage, crop rotation, and amendment effects on long-term C sequestration. Determine guidelines for biomass removal for energy production and its impacts on important soil properties and processes across Inland Pacific Northwest precipitation zones. 2.) Determine impacts of cropping and tillage systems on water quality and maintenance of the soil resource base. 3.) Develop conservation cropping and tillage systems that improve agroecosystem performance (production, stability and sustainability) and minimize adverse environmental impacts to air, water, and soil resources. 3.a.) Develop and evaluate tillage and crop residue management practices for successful conservation systems. 1b.Approach (from AD-416) Transitional soil microbial communities will be identified in fields undergoing changes in management from conventional tillage to reduced or no-till systems. Microbial activity will be estimated by CO_2 flux. Populations of viable microorganisms will be estimated by most-probable-number assay or plate counts. Communities will be analyzed by substrate utilization patterns using the BIOLOG system. From these microbial analyses we will calculate microbial diversity, overall microbial populations, microbial activity and community profiles. The effects of different C substances will be examined in controlled plot experiments. Greenhouse-gas fluxes from three cropping system scenarios will be determined using GRACEnet protocols. Development and refinement of CQESTR will include recalibration, revalidation, compilation of data inputs and default parameters relevant to soils, and compilation of management and climatic conditions for participating ARS locations. Two small watersheds, one in a no-till four-year rotation and the second in conventional-till winter wheat–fallow, will be used in a paired design to determine impacts of cropping and tillage systems on soil and water quality. Temperature and moisture profiles will be used to characterize the effects of tillage methods, timings, depths, and soil types on heat and water flow in order to evaluate and develop management practices for summer fallow systems. We will evaluate a system that both harvests wheat and prepares crop residue for optimum no-till drill performance under heavy residue conditions. Replacing 5356-12000-008-00D 10/01/2006. Associated with Pullman, WA, project 5348-11120-004-00D. 4.Accomplishments Carbon balance model for evaluating carbon storage or loss, CQESTR, improved. At the Columbia Plateau Conservation Research Center, Pendleton, OR, CQESTR was modified to fully utilize cumulative degree-days to improve its predictions for Southeastern and subtropical areas. The prospect of storing carbon (C) in soil provides an opportunity for agriculture to contribute to the reduction of carbon dioxide in the atmosphere, but models for predicted results are needed. With this recent modification, CQESTR has potential to be used nationwide to assess long-term effects of cropping systems or crop residue removal on C storage/loss in agricultural soils. The model is valuable for land managers and NRCS personnel at the field scale, and for management planning for C credits. Problem Area 3, Focus Area 2: Soil carbon dynamics. Focus Area 3: Effects of management on soil carbon. Cross-Location Project: GRACEnet. Problem Area 6: Impact on soil of residue removal for bio-fuel production. Tillage impact on winter wheat yield and net return to the producer measured. A field experiment comparing conventional tillage-based summer fallow with no-till summer fallow and direct seeding was conducted at the Columbia Plateau Conservation Research Center, Pendleton, OR, to evaluate the effects of tillage and N fertilization rates on winter wheat yields and economic returns. The predominant dryland cropping system in the low and intermediate rainfall areas of the Pacific Northwest is winter wheat-summer fallow using conventional tillage; however such a system increases the loss of soil organic matter and decreases soil quality. Winter wheat grain yields and costs were similar in the conventional tillage and the no-till, direct-seed systems. Yield and partial net return were greatest at 120 lbs nitrogen per acre in the conventional tillage plots, but small improvements in no-till systems or incentive programs should prove successful in increasing its use. Problem Area 5, Focus Area 1: Better knowledge and technologies to expand the use and development of new conservation systems. 5.Significant Activities that Support Special Target Populations None. 6.Technology Transfer Number of non-peer reviewed presentations and proceedings 11 Number of newspaper articles and other presentations for non-science audiences 10